Non-small cell lung cancer cells often over-express vascular endothelial growth factor (VEGF) receptors. Besides, the expression of the VEGF ligands is also correlated with increased tumor angiogenesis, as well as shortened survival time. One study treated with VEGF-directed monoclonal antibody (bevacizumab) and VEGFR and platelet-derived growth factor receptor (PDGFR) small molecule inhibitors (sunitinib) showed that some non-small cell lung cancer patients are with anti-tumor activity.